not able to run Microsoft Quickstart examples

The source code that generated this unhandled exception can only be shown when compiled in debug mode. To enable this, please follow one of the below steps, then request the URL:
 
1. Add a "Debug=true" directive at the top of the file that generated the error. Example:
 
<%@ Page Language="C#" Debug="true" %>
 
or:
 
2) Add the following section to the configuration file of your application:
 
<configuration>
<system.web>
	 <compilation debug="true"/>
</system.web>
</configuration>
 
Note that this second technique will cause all files within a given application to be compiled in debug mode. The first technique will cause only that particular file to be compiled in debug mode.
 
Important: Running applications in debug mode does incur a memory/performance overhead. You should make sure that an application has debugging disabled before deploying into production scenario. 

 
[SqlException: SQL Server does not exist or access denied.]
System.Data.SqlClient.ConnectionPool.GetConnection  (Boolean& isInTransaction) +472
System.Data.SqlClient.SqlConnectionPoolManager.Get  PooledConnection(SqlConnectionString options, Boolean& isInTransaction) +372
System.Data.SqlClient.SqlConnection.Open() +383
System.Data.Common.DbDataAdapter.QuietOpen(IDbConn  ection connection, ConnectionState& originalState) +44
System.Data.Common.DbDataAdapter.FillFromCommand(O  bject data, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +304
System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +77
System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, String srcTable) +36
_ASP.datalist1_aspx.Page_Load(Object Sender, EventArgs E) +95
System.Web.UI.Control.OnLoad(EventArgs e) +67
System.Web.UI.Control.LoadRecursive() +35
System.Web.UI.Page.ProcessRequestMain() +731